The pullies are fine. My cutlass has an XP cam and 105lb springs and i shift around 6700-6800 with it. I have very agressively ported heads though and stock heads wont go near that high without falling on their face. I set most cars around 6300 shift points with the XP cam and it seems to be a good spot with stock heads, ported heads you can go a little higher and I wouldnt suggest the rpms I am running. The power starts to fade at about 6600 in my car. Make sure you are actually making the shift around 6300. You will likely need to have a lower shift point than that because stock or most rebuilt transmissions wont shift right when you command it to in the tune and there is often a 100-300 rpm lag on the shift so it will take some testing to get it where you want. The top of 2nd gear will tell you if you are revving too high as you will feel the power nose off if your shifts are too high. Dont be as concerned with the engine not wanting those kind of rpms because it will handle it just fine, focus on how the power curve feels.
